There has been progressive development of compounds that are more and more potent and/or selective as agonists of A2A adenosine receptors (AR) based on radioligand binding assays and physiological responses. For example, U.S. Pat. No. 6,232,297 to Linden, et al. describes compounds having the general formula:
wherein each R can be H, X can be ethylaminocarbonyl and R1 can be 4-methoxycarbonylcyclohexylmethyl (DWH-146e). These compounds are reported to be A2A agonists.
U.S. Pat. No. 7,214,665 to Linden, et al. describes compounds having the general formula:
wherein R7 can be H, X can be an ether or an amide, CR1R2 can be CH2, and Z can be a heterocyclic ring. These compounds are reported to be A2A agonists.
U.S. Pat. Appl. No. 2006/004088 to Rieger, et al. describes compounds having the general formula:
wherein R7 can be H, X can be a cycloalkyl-substituted ether or amide, CR1R2 can be CH2, and Z can be a heterocyclic ring. These compounds are reported to be A2A agonists.
U.S. Pat. Appl. No. 2007/0270373 to Rieger, et al. describes compounds having the general formula:
wherein NR1R2 can be NH2, R4 can be an ether or an amide, R5 can be ethynyl, Y can be O or NR1, and Z can be an aryl or heteroaryl. These compounds are reported to be A2A agonists.
Even in view of the above, a continuing need exists for A2 adenosine receptor agonists useful for therapeutic applications.